Our ears are always picks out the sounds of human scream in the background of other, even more loud noises. Department of Science “Gazety.Ru” tells what are the features of a cry, as the cry of help in creating alarm sounds, and that is why people are afraid of these sounds.
These days, even being in your own apartment, you rarely stay in silence. Everyday life is filled with a wide variety of sounds: the noise of cars passing on the road beneath the window, the sound of the party, held in the apartment of the neighbors above, voices and music coming from the TV or radio. But even amid all these sounds are often very loud,
our ears always snatch the sound of human screams – whether adult or child scream.
An international team of researchers led by David Poppel from New York University decided to find out what is special about the human cry . The full text of scientific articles can be available in the journal Current Biology.
«If you come to the man on the street and ask him what is special in a scream, he usually says that the sound of shouting louder and higher than the sounds of a different origin. However, there are many other sounds that have similar properties, “- says David Poppel.
Scientists have conducted a series of experiments, allowing volunteers to listen to the sound of human screams taken on the site YouTube, from the movies, and recorded specifically for the experience. At the time listening to records, researchers measured the activity of various brain regions tested. They then compared the data with information about the brain’s response to other sounds: quiet human speech in different languages, the noise of cars, the roar of aircraft, as well as the sounds of sirens and alarms.
The results were quite surprising. It was found that
sounds of screams and the sounds of sirens and alarms cause the activity of one and the same area of the brain, not associated with the perception of sound information.
This area is called the amygdala is responsible for the formation of emotions, both negative (fear), and positive (pleasure).
The size of the amygdala is positively correlated with the degree of aggressive behavior. Scientists believe that the formation of some mental disorders such as depression, autism, anxiety or phobias, it is associated with disorders of the amygdala.
The study concluded that people are able to allocate the sound of screams and sirens in the background of other noise is due to the fact that they are responsible for the formation of the activated brain region fear. Further work on the analysis of different types of sounds found that screams and sirens have characteristics that distinguish them from all other noises. So the quality of steel
increased sharpness of sound, that is, its ability to greatly change the volume and height in a very short time.
The oscillation frequency of the sound wave scream may vary from 30 to 150 Hz, while for quiet human speech does not exceed the range of 4-5 Hz.
In order to confirm the findings, the researchers asked participants to listen to several different experimental screams, distinguished by their harshness, and say which of them sound more scary. People said that the most terrible for them began screaming with the largest rate of change of the volume and pitch. Car alarms and fire alarms have the same qualities, scientists say.
The researchers are going to continue to study the cries of the next step in their work will be figuring out different Is the cry of a small child from screaming adult. In addition, the scientists want to determine how animals perceive “cries” of representatives of their own species. If it turns out that these sounds activated the amygdala and the brain, it would mean that
the ability to scream formed in the course of evolution as a specialized means of communication.
By the way, according to the findings of other research groups, women’s and children’s cries rank sixth and ninth place, respectively, in the top ten of the most unpleasant to the human ear sounds. The list also includes a grinding blade on the glass, chalk squeaking and nails on a blackboard, the sound of a fork on a glass, automotive brakes screeching, and the noise of the grinding machine and electric drill. The most pleasant sound of applause were called, children’s laughter, thunder and the sound of water. The full text of scientific articles that constituted the lists can be available in The Journal of Neuroscience.
In addition, the researchers warn that too high a level of daily noise (sounds coming from the highways and from the apartment to make repairs neighbors) can cause serious health problems. Researchers found that people living in areas with active traffic (noise exceeds 60 dB volume), end up in hospital with a stroke of 5% more than those who live in quieter areas. Older people are susceptible to noise even more: in their case, the noise increases the risk of stroke by 9%. Read more about the dangers of extraneous sounds that accompany us every day, you can read in the European Heart Journal.
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